Erin has become the first hurricane of the Atlantic season with strong waves and rip currents possible along the East Coast of the United States as early as next week.

A westward-moving tropical wave could produce an area of low pressure in the tropical Atlantic late in the week of Aug. 18, the hurricane center said on Aug. 16. The center shows a 20% chance of storm formation over the next week.

Tropical Storm Erin is expected to become a hurricane later today, Aug. 15, and a Category 4 hurricane with maximum sustained winds of 130 mph over the weekend. A major hurricane is a Category 3 or stronger, with maximum sustained winds of at least 111 mph.

Tropical Storm Erin is approaching Puerto Rico and the Virgin Islands, bringing heavy rains that could cause flooding and landslides.